To date in electronic motor controls there are used for the motor moment regulation and/or motor moment restriction motor moment constants kM. With the aid of this relationship:MMot=kM·IMot  (1)the produced inner motor moment (without friction losses, therefore inner moment) can be determined on the basis of the measured or regulated motor current IMot.
As a rule, thereby the motor moment constant is determined by measurement techniques over a statistically sufficient number of motors on a motor test bed and then stored as constant in the motor control.
For the determination of the motor moment constant there is employed as a rule a torque measurement device and a current measurement device and the motor moment constant is then calculated via the formula
                              k          M                =                              M            Mot                                I            Mot                                              (        2        )            
It is here clear that a great measuring outlay is necessary for the determination of the motor moment constants and only (depending on application) a mean, maximum or minimum value of the motor moment constant can be employed for the motor control, insofar as no calibration is carried out for each motor.